Ultrasonic velocity, density, viscosity measurements were conducted for the drug Aripiprazole loaded with different ratio of polymer Polyethylene Glycol. The experimental data were used to determine acoustical parameters such as adiabatic compressibility, acoustic impedance, relaxation time, free length, relative association etc. Morphology and compatibility of polymeric drug particles were studied using SEM and FTIR. The outcomes were expressed in terms of the molecular interaction and the variation in parameters under varying ratio of polymer in drug-polymer suspension. Concluding remarks regarding intermolecular interactions are also provided.